Napoleon Bonaparte was, seemingly arbitrarily, chosen by the Directory for the position of general of the French Army of Italy. This proved to be a good decision by the Directory, but they had no way of knowing that Napoleon would perform so well. There were generals in Italy with a bigger and better resume than Napoleon at the time, namely Masséna and Augereau. What factors caused the Directory to appoint Napoleon to command the campaign in Italy, rather than someone with a better claim to command? Expanding the question, if the Directory was so confident in Napoleon, why didn't they assign him to one of the two armies along the Rhine?
Napoleon Bonaparte was the protégé of Paul Barras, the strongest man of the time, member of the Directoire, who favored his military career and probably monitored his matrimonial plans (Josephine de Beauharnais was Barras' mistress when he introduced her to Bonaparte). Possible bargains between the two men in both fields have been the subject of speculations by historians.
Napoleon Bonaparte was already, thanks to Barras, Commander-in-Chief of French Interior Army, leading more than 5.000 troops in and around Paris. The Convention had gladly used this force for repressing the royalist Vendémiaire insurrection in October 1795, but leaving it under a general as ambitious as Bonaparte would be uncomfortable for the Directoire, so it felt safer to send him to a theater far from the capital and replace him with general Hatry, obedient and devoid of political ambition. The Coup of 18 Brumaire in 1799 will confirm that this prudence wasn't totally uncalled for...
his new wife, Josephine Beauharnais, had connections; and
only Napoleon was interested in such a dismal and unsupported command.
When Napoleon arrived the Army of Italy was unfed, unpaid, largely unshod, outnumbered, and severely mutinous. It wasn't that the Directory was so confident in Napoleon's abilities - they were desperate, and willing to gamble on an unknown in this minor and ignored theater.